REVISION OF THE JUMPING MICE OF THE GENUS ZAPUS. 23 



over the plains of Assiuiboia and Saskatchewan, where it grades into 

 the form here described as subspecies minor. 



Specimens examined. Total number, 101, from the following localities: 



Alberta: Crow Nest Pass (Rocky Mountains near forty-ninth parallel), 1; 



Henry House, 2; 15 miles south of Henry House, 3. 

 British Columbia: Field, 3; Glacier, 1. 

 Montana: Bear Paw Mountains, 6; Big Snowy Mountains, 12; Blackfoot 



Agency, 2; Fort Ellis, 1; Paola, 1; Pryor Mountains, 1; St. Marys Lake, 



13; Summit, 5; Upper Stillwater Lake, 2. 

 Idaho : 1'reuss Mountains, 8; Salmon River Mountains, 5. 

 Wyoming: Clark Fork, 1; La Barge Creek, 11; Yellowstone Lake, 1. 

 Colorado: Co<hetope Pass, 1; Florida (type locality), 5; Fort Garland, 10; 



Gold Hill, 2; Rocky Mountains (39), 1. 

 New Mexico: Camp Burgwyn, 2; Santa Fe, 1. 



ZAPUS PRINCEPS MINOR subsp. nov. Saskatchewan Jumping Mouse. 



Type from Wingard, near Carlton House, Saskatchewan, No. 73673, 9 ad., U. S. Nat. 

 Museum, Biological Survey Coll. Collected July 23, 1895, by J. Alden Loring. 

 Original No. 3123. 



Geographic distribution. Plains of Saskatchewan; limits of range 

 unknown. 



General characters. Similar to Zapus princeps, but smaller and differ- 

 ing in color and cranial characters. 



Color. Summer pelage: Similar to Z.princtps, but dorsal area darker; 

 lower parts suffused with salmon. Fall pelage with dorsal area thickly 

 necked with yellowish and sides yellowish olive; lower parts much as 

 in summer. 



Cranial characters. Skulls of the present form from Osier and \Vin- 

 gard, Saskatchewan, compared with those of Z. princeps from Colorado, 

 differ as follows: Smaller; rostrum shorter and more deflected; nasals 

 much narrower anteriorly; brain case relatively higher; interpterygoid 

 fossa shallower. 



Measurements. Average of 10 specimens from Osier, Saskatchewan: 

 Total length, 219; tail vertebra", 131; hind foot, 29.9. Average of 2 

 from type locality: Total length, 220; tail vertebrae, 131.5; hind foot, 

 28. Skull: Average of 3 skulls from Osier, Saskatchewan: Easilar 

 length, 18.7; zygomatic breadth, J2.2; mastoid breadth, 10.7; interor- 

 bital constriction, 4.4; incisor to postpalatal notch, 9; foramen mag- 

 num to postpalatal notch, 8.3; fronto-palatal depth at middle of molar 

 series, 6.7. 



General remarks. Z. minor is a well-marked subspecies requiring 

 comparison only with Z. princeps. Jt is evidently the northern plains 

 representative of that species, probably intergrading with it in Assini- 

 boia and eastern Alberta near the United States boundary and along 

 the eastern base of the Canadian Kockies. Lack of specimens from 

 this region makes it impossible to conclusively settle this point. 



Specimens examined. Total number, 21, from the following localities: 



Saskatchewan: Osier, 15; Wingard (type locality), 3. 

 Assiniboia: Indian Head, 3. 



